Repairing an Onkyo HT-R380

Onkyo HT-R380

I picked up an old Onkyo HT-R380 amplifier that was stuck in standby / protect mode so pulled it apart to find out what the problem was.

Onkyo HT-R380

This is a typical fault condition with a lot of old amplifiers as something fails and triggers one of many protection circuits that switch the unit off.

onkyo HT-R380 circuit boards

If you’re fixing one of these yourself it won’t work with the back panel removed as it forms a ground connection between the standby board and the main board.

I’ve produced a YouTube video that takes you through how this Onkyo powers up and what causes it to switch into protect or standby mode.

I tracked the fault down to a Sanyo STK module that’s obsolete. I brought a cloned one from China and it was more faulty then the original faulty one!

Note: If you don’t know what you’re doing don’t start poking around inside these things. There’s +/- 50v on the circuit boards and live mains on things like the transformer. You could do a lot of damage to yourself or the amplifier.